This invention relates generally to multi-functional apparatuses and specifically to an intermittent rotary motion mechanism for use in an automotive vehicle.
Almost all automotive vehicles have a single or a pair of windshield wiper assemblies. These assemblies traditionally include rubber wiper blades mounted upon claw brackets. These claw brackets are pivotably attached to wiper arms mounted upon rotating shafts. The shafts are either directly driven by electric motors or driven by a single electric motor which actuates a series or parallel-coupled four bar linkage mechanism. It is further known to provide a wiper system, in combination with a wash device, to clean headlamps for automotive vehicles.
It is also common to employ a window wiper assembly for cleaning rear windows of automotive vehicles. Typically, these types of rear window wiper assemblies include a wiper blade mounted upon a bracket which is coupled to a wiper arm. The wiper arm is attached to a wiper shaft rotatably driven in a cyclical oscillating manner by a helical gear. A reversible, fractional horsepower, direct current electric motor serves to actuate the helical gear through an armature shaft-mounted worm gear enmeshed therewith. This type of rear window wiper arrangement is usually mounted upon a pivoting liftgate of a minivan, station wagon, sport-utility vehicle or the like. One such example is disclosed in U.S. Pat. No. 5,519,258 entitled "System and Method for Controlling Vehicle Lift Gate Window Wiper" which issued to Stroven et al. on May 21, 1996.
Some conventional vehicles also provide a rear window release lock or latch, actuated by a solenoid, which can be unlocked to allow for upward pivotal movement of a rear window in relation to the otherwise stationary liftgate. In combination therewith, a separate liftgate lock is often mounted upon the liftgate door for fastening the liftgate to the body thereby preventing inadvertent pivotal opening. This liftgate lock is traditionally operated by manual key or handle rotation, or through a separate electric motor or solenoid.
Separate motors or solenoids are commonly required to actuate these various locks and the wiper. The traditional need for such a multiplicity of electromagnetic devices has increased the automotive vehicle weight and cost while further proving difficult to package within the often small spaces provided. This added weight is especially detrimental when the window wiper mechanism, rear window lock and liftgate lock, as well as their distinct respective electromagnetic devices, are all incorporated within the pivoting liftgate. Not only is the piece cost increased due to this multiplicity of electromagnetic devices, but the assembly cost, part number proliferation and handling costs, electric wiring costs, objectional motor noise, and failure modes are increased.
Furthermore, U.S. Pat. No. 3,688,332 entitled "Mechanism for Opening and Closing a Cover for a Concealed Windshield Wiper System" which issued to Bellware on Sep. 5, 1972, discloses a windshield wiper driven by an electric motor and an interruptable driving connection controlled by a separate electromagnet. This device further employed levers and pivot pins to open and close a cover.
More recently, WO 96/33891 entitled "Multi-Functional Apparatus Employing an Intermittent Motion Mechanism," WO 96/33893 entitled "Multi-Functional Apparatus Employing an Electromagnetic Device," and WO 96/33892 entitled "Control System for an Automotive Vehicle Multi-Functional Apparatus," all of which were published on Oct. 31, 1996, disclose a significantly improved system wherein a single electromagnetic device can selectively operate intermittent motion mechanisms coupled to a window wiper, a door lock, a window release lock and the like. Notwithstanding, these devices require further refinement and improvement. For example, if the window wiper is frozen onto a window, a door could not be unlocked, with the geneva and starwheel mechanism constructions. Moreover, a car wash or bumpy road could cause the window wiper to undesirably and destructively move from its parked position when a wiper clutch is disengaged, for the split-shaft clutch construction. The split-shaft clutch embodiment also requires further improvements and refinements to increase the durability and robustness of design, while further minimizing the weight of the unit.